This invention relates to a coupling a valve for vacuum-tight joining of stationary and movable evacuatable chambers. The valve is installed between confronting chamber walls which are displaceable parallelly against one another and includes a frame which is fastened to the one chamber wall and which is joined by a resilient member to a second movable frame which can be brought into engagement with the other chamber wall.
Coupling valves of the initially described kind are known; they serve for the vacuum-tight joining together of movable and stationary vacuum chambers which have to be separated for loading purposes, for example. For example, there are vacuum arc furnaces in which an upper part of the furnace has to be separated, (for inserting a fusible electrode), from a bottom part in which there is situated a mold for the production of a metal ingot from the material of the melted electrode. Here, however, the coupling valve plays a passive role, i.e., it serves for the compensation of any alignment errors. In this case, the movable frame is joined to the confronting chamber wall under the action of springs (German Patent No. 1 816 055). The ability of such a coupling valve to operate, however, requires that the two vacuum chambers or chamber parts that are to be joined together be additionally movable towards and away from one another, i.e., that at least one of the two vacuum chambers be provided with a drive means which enables the springs pertaining to the coupling valve to be compressed and/or relieved. Such a coupling valve, therefore, cannot be used in vacuum systems in which the distance between the two vacuum chambers or the confronting chamber walls is invariable or variable to only a very slight extent.
In vacuum systems, especially vacuum coating systems, the necessity frequently exists of bringing movable loading chambers into engagement with a stationary coating chamber. In the case of a plurality of loading chamber, this can be brought about by placing these chambers alongside one another on a carriage and enabling them to be coupled to the coating chamber successively by transverse movement. This transverse movement or shuttling requires guides such as rails and wheels, for example, which largely prevent the movable and the stationary vacuum chambers from being brought against one another. It must also be considered that two vacuum chambers which are joined together by a resilient means and evacuated are pressed against one another with a force which corresponds to the atmospheric pressure multiplied by the area of the coupling cross section of the two vacuum chambers. This force has to be absorbed by appropriate means.